10-06-2020, 03:20 PM
(This post was last modified: 10-06-2020, 03:23 PM by Mike Watterson.)
You can run class B push pull and get about x4 the power of one. They were usually class C push pull in transmitters. An LOPT can essentially be class C, but not push pull. You could run the frame drive push pull class B.
They can do 800W each for a very short period of time.
Clue is the filament current. It's x20 the 1j24b (220mA vs 11mA).
Do note these are designed as 1.2V filament (or 2.4V ) for rechargeable or NiCd regulated LT systems rather than the 1.4V of the USA & Western Europe battery valves. Eastern Europe and USSR had actually 1.2V versions of the B7G types. This family were used in satellites, bomb/shell proximity fuzes (simple radar), MiG fighter, vehicle / manpack terrestrial, and one Forestry R/T set, which is closest they got to "consumer".
The 1j29b and 1p24b with filament in series mode work well off 1.8V to 2.1 Lead Acid cell. Hence triodised versions can be used in old pre-1928 battery sets. Two or three triodised 1p24b will replace a PX4. I did connect up three and experimented with different bias and filament arrangements, but didn't try it in anything wanting a PX4. The earlier PX4 is lower power and can easily be replaced by a triodised pair with 2.4V each filaments and additional pair of resistors for 4V which also help balance the loading.
They can do 800W each for a very short period of time.
Clue is the filament current. It's x20 the 1j24b (220mA vs 11mA).
Do note these are designed as 1.2V filament (or 2.4V ) for rechargeable or NiCd regulated LT systems rather than the 1.4V of the USA & Western Europe battery valves. Eastern Europe and USSR had actually 1.2V versions of the B7G types. This family were used in satellites, bomb/shell proximity fuzes (simple radar), MiG fighter, vehicle / manpack terrestrial, and one Forestry R/T set, which is closest they got to "consumer".
The 1j29b and 1p24b with filament in series mode work well off 1.8V to 2.1 Lead Acid cell. Hence triodised versions can be used in old pre-1928 battery sets. Two or three triodised 1p24b will replace a PX4. I did connect up three and experimented with different bias and filament arrangements, but didn't try it in anything wanting a PX4. The earlier PX4 is lower power and can easily be replaced by a triodised pair with 2.4V each filaments and additional pair of resistors for 4V which also help balance the loading.
